Plug-fuse.



H. U. BADEAU 82; P. P. POOLE.

PLUG FUSE.

APPLICATION FILED DEO.19,1908.

Patented Apr. 27, 1909.

- rr/r/mssa J. -2i W UNITED STATES PATENT HARRY U. BADEAU ANDFREDERICKP. POOLE, OF BRIDGEPORT, OONNEOTICUT, ASSIGNORS TO THE BRYANT ELECTRICCOMPANY, OF BRIDGEPORT, CONNEOTIOUEA CORPORATION OF CONNECTICUT.

' PLUG-FUSE Specification of Letters Patent. Patented April 27, 1909.Application filed December 19, 1908. Serial No. 463,271.

T all whom it may concem:

Be it known that we, Hnnnr U. Bnnnriu and FREDERICK P. Poona, bothcitizens of the United States of America and both residing in the cityof Bridgeport, in the county of Fairfield, in the State of Connecticut,have invented certain'new and use ful Improvements in Plug-F uses, ofwhich the following is a specification.

Our invention relates to the class of electrical fuses which arecommonly termed plug fuses, and which comprise a cup-shaped body ofporcelain or other insulating material carrying on the outside terminalsto enter and engage with an Edison or other suitable type of receptacleand closed by a capand containing within the insulati body a fuseconnecting the terminals.

' In a trial practice it has been found necessary either to provide fuseplugs with Vent holes or to fill the plug with smother ing' powderaround the fuse. The vent holes are objectionable because they allow theescape of fire therethrough, and the use D is a. flat strip of fusiblematerial having at a suitable point a part of reduced cros section, asbyperforating it at (Z,.Fig. 3, to provide the requisite capacity tomelt on an abnormal increase of current. ()ne end' of this fuse strip Dis soldered to the end of theterminal B, while the other passes up overthe bridge (Z in the shell into a pocket Z), where it is soldered to thescrew shell C. lVe have shown it soldered to the inside of the shell,but this forms no part of our invention, so long as sufficient solder isprovided, so that practically no vent hole is left at that point.

As will be seen on reference to Fig. 5, the mouth of the'cup-shaped bodyis formed without any radial grooves or notches which are commonlyprovided for vent purposes, so that when the mica or other suitablesheet F is placed over the mouth of the cup, no intentional vent is leftfrom the interior of the fuse plug. The mica coveris held in place asusual by an annular flanged ring G, the lower end of which. is flangedunder of the powder is objectionable because of the shoulder a of thecup-shaped body after ,expense and other reasons. it has been put inplace, and this ring may The object of our invention is to so conbeprevented from turning by bending a st-ruct a plug fuse that withoutusing any portlon of it Into the notch g, Figs 1, 2 and powder or otherfilling material, vent holes 5, formed on the underside'o the shouldermay be dispensed with and thereby danger a preferably at a point dametrically opof fire greatly reduced and this without liaposite thewell 5. bility of bursting the plug when the fuse Ne have discovered,and by careful tests burns out. This object we attain in the have provedthat a plug fuse thus conmanne Which W will now describestructed withoutany filling, and without 5 In the accompanying drawings Figure 1 anyvent holes, can be relied onto work peris a vertical section of ourimproved fuse fectly and with certainty. The reason why plug; Fig. 2 isa corresponding section we are thus able to dispense with vent holesshowing the plug in the course of cons rucand with filling is due to thecombination of tion; Fig. 3 is a section on the line 33, the ventlessunfilled covered plug with a fiat 40 Fig. 1; Fig. 4 is a plan view oftheplug fuse strip with the reduced cross-section, when the cap has beenremoved; Fig. 5 is giving a definite melting point well down aperspective view of the plug when the cap in the .cup in place oftheordinary fuse wire has been removed. i of round cross-section. Webelieve the cr- A is the cup shaped body of porcelain or planation to bethat thereby we get the ve other suitable insulating material havingsesmallest amount of metal allowable to be cured in its lower end acentral terminal or fused and therefore a moderate quantity of contactB, and around the outside of its gases produced, while on the otherhand, the body a screw shell C to adapt it for applicubic capacity ofthe plug is relatively large, cation to the Edison'type of receptacle orallowing room for expansion and at the socket. The exterior of theporcelain where same time the cover of the fuse plug has a certainamount of elasticity and yieldsto some extent to the pressure, andfinally, if the internal pressure produced is greater than can be takencare of by the elements named, that pressure will then start the thescrew shell C is to be held has preferably formed upon it threads orportions of threads with which the screw shell may engage so that thelatter cannot be removed except by turning it upon the body.

around the entire circumference ,of the mouth of the plug that thereisno danger of any fire escaping and no danger of a burst. The ring willsimply become loosened a little.

We claim as our invention- .1. A ventless fuse plug, having a cupshapedinsulating body with terminals and containing within it only a flat fusestrip, having at a point within the cup a reduced cross-section for themelting-point, in combination-with an inclosing cover.

2. A ventless fuse plug, having an unfilled cup-shaped body withterminals and an internal fusible flat strip; having at a point withinthe cup a. reduced cross-section for the melting point, incombinationwith an inclosing cover, adapted to yield a little without allowing thefire to escape when the fuse 'blows. 'l

3. A ventless fuse plug, hz iviiig an unfilled cup-shaped insulatingbody with terminals and an internal fusible flat strip having at a pointwithin the cup a reduced cross-section for the melting point, incombination with a flexible covering disk and a flanged retaining ring,substantially as de- ,scribed- In testimony whereof we have signed ournames to this specification, in the presence of two subscribingwitnesses.

HARRY U. BADEAU. FREDERICK P. POOLE. Vitnesses G. W. GOODRIDGE, H. W.GoLnsnonouon.

